详解关于Vue单元测试的几个坑

<g-input v-model="message"></g-input>

it("支持事件", () => {
   ["change", "input", "focus", "blur"].forEach(eventName => {
    vm = new Constructor({}).$mount();
    const callback = sinon.fake();
    vm.$on(eventName, callback);
    let event = new Event(eventName);
    Object.defineProperty(event, "target", {
     value: { value: "hi" },
     enumerable: true
    });
    let inputElement = vm.$el.querySelector("input");
    inputElement.dispatchEvent(event);
    expect(callback).to.have.been.calledWith("hi");
   });
  });

it("接受gutter", function(done) {
  Vue.component("g-row", Row);
  Vue.component("g-col", Col);
  const div = document.createElement("div");
  document.body.appendChild(div);
  div.innerHTML = `
  <g-row gutter="20"> 
    <g-col></g-col> 
    <g-col></g-col> 
  </g-row>`;
  const vm = new Vue({
   el: div
  });
  setTimeout(() => {
   const row = vm.$el.querySelector(".row");
   expect(getComputedStyle(row).marginRight).to.eq("-10px");
   expect(getComputedStyle(row).marginLeft).to.eq("-10px");
   const cols = vm.$el.querySelectorAll(".col");
   expect(getComputedStyle(cols[0]).paddingRight).to.eq("10px");
   expect(getComputedStyle(cols[1]).paddingLeft).to.eq("10px");
   done();
   vm.$el.remove();
   vm.$destroy();
  }, 0);
 });

it("接受gutter", function(done) {
  Vue.component("g-row", Row);
  Vue.component("g-col", Col);
  const div = document.createElement("div");
  document.body.appendChild(div);
  div.innerHTML = `
  <g-row gutter="20"> 
    <g-col></g-col> 
    <g-col></g-col> 
  </g-row>`;
  const vm = new Vue({
   el: div
  });
  setTimeout(() => {
   const row = vm.$el.querySelector(".row");
   expect(getComputedStyle(row).marginRight).to.eq("-10px");
   expect(getComputedStyle(row).marginLeft).to.eq("-10px");
   const cols = vm.$el.querySelectorAll(".col");
   expect(getComputedStyle(cols[0]).paddingRight).to.eq("10px");
   expect(getComputedStyle(cols[1]).paddingLeft).to.eq("10px");
   done();
   vm.$el.remove();
   vm.$destroy();
  }, 0);
 });

vm.$el.remove();
 vm.$destroy();

var div = document. getElementById('xxx')
div.onclick = function() {
  ///code
}
setTimeout(function(){
  div. remove()
}, 3000)

var div = document. getElementById('xxx')
div.onclick = function() {
  ///code
}
setTimeout(function(){
  div = mull
}, 3000)

var div = document. getElementById('xxx')
div.onclick = function() {
  ///code
}
setTimeout(function(){
  var div2 = document. getElementById('xxx')
}, 3000)